共查询到20条相似文献，搜索用时 262 毫秒
1.
2.
定理 设α、β、γ∈Ｒ ,则有ｃｏｓαｓｉｎ ( β -γ) ｃｏｓβｓｉｎ (γ -α) ｃｏｓγｓｉｎ (α - β) =0 . ( 1)ｓｉｎαｓｉｎ ( β -γ) ｓｉｎβｓｉｎ (γ -α) ｓｉｎγｓｉｎ (α - β) =0 . ( 2 )证明 构造二元一次方程组ｘｃｏｓα ｙｃｏｓβ =ｃｏｓγ ,(ａ)ｘｓｉｎα ｙｓｉｎβ =ｓｉｎγ . (ｂ)由 (ａ)、 (ｂ)两式可得ｘｓｉｎ(α- β) =ｓｉｎ(γ - β) ,(ｃ)ｙｓｉｎ(α- β) =ｓｉｎ(α -γ) . (ｄ) 将 (ａ)式两边同乘ｓｉｎ (α - β)后 ,再将(ｃ)、 (ｄ)两式代入即得 ( 1) .将 (ｂ)式两边同乘ｓｉｎ (… 相似文献
3.
陈平平 《南京晓庄学院学报》2004,20(3):62-66
宋代杰出学者苏轼 ( 1 0 3 6— 1 1 0 1 )。亦是我国古代牡丹研究颇有成就的先驱者之一。他的《牡丹记叙》和三十多首有真知灼见的牡丹诗 ,对我国牡丹研究的科学历史与文化作出了独特的贡献 ;证实了北宋中期我国东部牡丹的栽培、研究、育种和牡丹文化 ,均有较快的发展和较高的水平 ;杭州为其中心 ,品种数目逾百 ;杭州太守沈立 ( 1 0 0 7— 1 0 78)早在熙宁五年 ( 1 0 72 )、就已撰写出我国和世界上最早的大型牡丹专著《牡丹记》十卷 相似文献
4.
课题通过系列实验研究探讨了聋人手语、唇读、中文阅读与语篇理解的认知基础:(1)手语是语言,有助于促进听觉障碍学生认知能力的发展。(2)唇读是一项复杂的视觉语言认知活动,能通过语音编码进行语音识别,与听觉语言认知具有相同的机理。(3)听觉障碍学生与正常学生尽管在中文阅读与语篇理解过程中认知加工方式的相似性大于差异性,但听觉障碍学生明显滞后于正常学生。据此,我们提出了构建聋人综合语言教育模式的思路,聋校在采用综合语言教育时不可偏废某种语言交流方式,应该根据听觉障碍学生个体的特点或者群体的特点来作出有效的选择。 相似文献
5.
血清γ -谷氨酰转肽酶 (γ -ＧＴ)测定对于某些肝、胆、胰疾病的诊断具有重要的临床价值。国内测定γ -ＧＴ活性多用对硝基苯胺和重氮试剂两种方法 ,其中以后者应用最广。但该重氮试剂法有耗时长 (2ｈ)、显色剂必须新鲜配制 ,基质液于冰箱贮存后易析出沉淀、反应体积大 (10ｍｌ)等缺点。本文对原测定方法的试剂构成及测定步骤进行了革新 ,克服了原法的缺点 ,具有简单、快速、准确的优点 ,所得结果和参考值与原法一致 ,值得推广应用。1 试剂1.1 原法基质液 (10ｍｍｏｌ/Ｌ) γ -谷氨酰 -α -萘胺10 8.4ｍｇ溶于 4 0ｍｌ硼酸缓冲液中 (可加… 相似文献
6.
用较简单的方法证明了:在Minkowski平面中,假设γ 1 和γ 2 是a到b的凸曲线,conuγ 1 conuγ 2 ,则|γ 1 |≤|γ 2 |;对任意单位向量p'和q',δ(p',q')≤1/2Ⅱ(M)|p',q'|.并得出一推论. 相似文献
7.
γ -氯丙基三乙氧基硅烷依次进行气相法二氧化硅固载化 ,甲基硒钠硒化 ,再与氯化钯反应 ,合成聚γ - (β -甲硒基 )丙基硅氧烷钯 (Ⅱ )配合物 ,研究其催化物芳基卤化物的酰胺化性能 . 相似文献
8.
中国宋代牡丹谱录种类考略 总被引：5，自引：4，他引：1
陈平平 《南京晓庄学院学报》2000,(4)
我国牡丹栽培历史悠久 ,而其专著则始见于宋代 ( 960— 1 2 79)。散见于历代古籍中的宋代牡丹谱录名称 ,经分析归纳数目约有 2 1种之多 :中原 9种、江浙 5种、蜀地 3种、跨地区 3种、不明者1种 ;现存 7种、残存 3种、亡佚 1 1种。其中 ,仲休 (或仲林 )的《越中牡丹花品》二卷 ( 986) ,欧阳修的《洛阳牡丹记》一卷 ( 1 0 34 )、沈太守的《牡丹记》十卷 ( 1 0 72之前 )、分别是我国和世界上最早、现存最早、最大型的牡丹专著。宋代产生了我国和世界上的第一代牡丹专著 ,证实我国是世界上研究牡丹最早的国家和古老的中心 相似文献
9.
王艳 《黔南民族师范学院学报》2006,26(3):35-37
论述γ-氨基丁酸(GABA)对蝙蝠听觉中枢的作用,包括对频率调谐曲线、发放率、听感受野、听声反应模式的影响,说明GABA在中枢中产生的抑制作用. 相似文献
10.
口译中源语认知和工作记忆影响效应研究 总被引：1，自引：0，他引：1
徐腾飞 《新疆师范大学学报(哲学社会科学版)》2015,(1):126-131
文本通过对口译中源语(SL)感知认知、听觉认知(AP)、"中枢执行程式"调控以及工作记忆阶段等的研究,分析出SL认知和工作记忆对口译操作的效应。研究结果发现:大脑神经系统兴奋度影响听觉系统SL感知能力,而中兴奋度时听觉系统SL感知表现状况最佳,由此可知"中枢执行程式"的指导和调控作用凸显在口译中的重要性,并得出激活惰连关系,实现从惰连关系到专联关系的转变有助于增强SL认知。研究发现口译工作记忆分为回声记忆、听觉整合、最佳模式信息识别和短时记忆四个阶段,各阶段记忆任务的顺利完成才能发挥口译最佳效果。 相似文献
11.
DEHGHANI Mohammad Hadi MAHVI Amir Hossein NAJAFPOOR Ali Asghar AZAM Kamal 《浙江大学学报(A卷英文版)》2007,8(9):1462-1468
The effectiveness of using acoustical (sonochemical) reactor for degradation of linear alkylbenzen sulfonate (LAS) from aqueous solution was investigated. LASs are anionic surfactants,found in relatively high amounts in domestic and industrial wastewaters. In this study,experiments on LAS solution were performed using methylene blue active substances (MBAS) method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2,0.5,0.8 and 1.0 mg/L,acoustic fre-quency of 130 kHz,applied power of 500 W and temperature of 18 °C～20 °C. At the conditions involved,LAS degradation was found to increase with increasing sonochemical time. In addition,as the concentration increased,the LAS degradation rate de-creased in the acoustical processor reactor. 相似文献
12.
Involvement of basolateral amygdala GABAA receptors in the effect of dexamethasone on memory in rats
Khajehpour L Alizadeh-Makvandi A Kesmati M Eshagh-Harooni H 《Journal of Zhejiang University. Science. B》2011,12(11):900-908
In this study we investigated whether GABAA receptors of the basolateral amygdala (BLA) interact with the effect of dexamethasone on the retrieval stage of memory. Adult
male Wistar rats were bilaterally cannulated in the BLA by stereotaxic surgery. The animals were trained in step-through apparatus
by induction of electric shock (1.5 mA, 3 s) and were tested for memory retrieval after 1 d. The time of latency for entering
the dark compartment of the instrument and the time spent by rats in this chamber were recorded for evaluation of the animals’
retrieval in passive avoidance memory. Administration of dexamethasone (0.3 and 0.9 mg/kg, subcutaneously (s.c.)), immediately
after training, enhanced memory retrieval. This effect was reduced by intra-BLA microinjection of muscimol (0.125, 0.250 and
0.500 μg/rat), when administered before 0.9 mg/kg of dexamethasone. Microinjection of bicuculline (0.75 μg/rat, intra-BLA)
with an ineffective dose of dexamethasone (0.1 mg/kg, s.c.) increased memory retrieval. However, the same doses of muscimol
and bicuculline without dexamethasone did not affect memory processes. Our data support reports that dexamethasone enhances
memory retrieval. It seems that GABAA receptors of the BLA mediate the effect of dexamethasone on memory retrieval in rats. 相似文献
13.
1999~2006年,对四川绵阳地区鼠耳蝠种类、数量、分布及部分生态习性进行了调查研究。共采集到鼠耳蝠6种,其中大足鼠耳蝠为中国特有种,IUCN RL(2003)将其列入接近受威胁的低危种(LR/nt)。中华鼠耳蝠被列入《中国物种红色名录》中的易危(VU)种。西南鼠耳蝠和须鼠耳蝠被列入《中国物种红色名录》中的近危(NT)种。青海鼠耳蝠为四川蝙蝠新记录。对鼠耳蝠的部分生态习性进行了描述。提出了鼠耳蝠命名和分类存在的一些问题,并探讨了几种鼠耳蝠的物种现状、保护及生态习性。 相似文献
14.
Liu Xiaotu 《东南大学学报》1996,(1)
ＡｐｐｒｏｘｉｍａｔｅＦｏｒｍｕｌａｅｆｏｒＣａｌｃｕｌａｔｉｎｇｔｈｅＤｅｆｌｅｃｔｉｏｎｏｎｔｈｅＳｕｒｆａｃｅｏｆＦｌｅｘｉｂｌｅＰａｖｅｍｅｎｔＨｕａｎｇＷｅｉ（黄卫）（ＴｒａｎｓｐｏｒｔａｔｉｏｎＣｏｌｅｇｅ，ＳｏｕｔｈｅａｓｔＵｎｉｖｅｒ... 相似文献
15.
蔡荣男 《广东技术师范学院学报》2007,(2):15-17,22
本文采取声学实验和音系分析相结合的方法,通过语音分析软件"桌上语音工作室"(MiniSpeechLab)1对泰语单字调的语音材料进行分析,考察了泰语声调的声学特征,得出每个声调的调型和调值.声学实验结果与传统记音结果相比较,既有相同点也有不同点. 相似文献
16.
G. Marimuthu 《Resonance》1996,1(5):40-48
Bats are capable of avoiding obstacles that they encounter, even in complete darkness. This is because they emit ultrasound (high frequency sound) and analyse the echo produced when the sound hits objects on their path. This article describes the hunting flight of bats and how echolocation is useful in prey capture. Prey capture without the aid of echolocation by some bats is also described. 相似文献
17.
Every evening, against the backdrop of a setting sun, scores of both insect and fruit eating bats emerge out in search of food. While most of the bats emerge from pre-existing structures such as caves, crevices and human habitation, some emerge from structures modified by their own efforts. Our interest is particularly in the fruit bats emerging out from modified foliage. Because of their role in the regeneration of tropical forests by dispersing huge numbers of seeds, fruit bats are of profound importance. In this article, we discuss the mating strategy adopted by the Indian short-nosed fruit batCynopterus sphinx, the mechanics of tent-making in this species, and some recent findings which argue for an alternative breeding strategy. 相似文献
18.
刘丽 《沈阳教育学院学报》2004,6(3):133-135
分析了声反馈产生的原因，探讨了提高多媒体报告厅扩声系统传声系统传声增益的对策。提出了使用频率均衡器、窄带滤波器反馈抑制器是已建多媒体报告厅抑制声反馈的最佳途径，提高音响调控人员的能力水平是当务之急。 相似文献
19.
The puzzle as to how bats navigate without colliding with obstacles and hunt tiny mosquitoes in complete darkness remained
unanswered for nearly 140 years after Lazzaro Spallanzani, who proposed at the close of the 18th century that bats possess
a ‘sixth sense’ for orientation. Donald Griffin solved the puzzle in 1938 with the help of world’s first ultrasound microphone
devised by the American physicist G W Pierce. Griffin called this sixth sense ‘echolocation’, which enables bats and marine
mammals such as whales, dolphins and porpoises to lead active lives under the cover of darkness. In this article we describe
the life of Donald Griffin and how he proved the existence of echolocation in bats. 相似文献
20.
Ching Yee Choi 《International Journal of Disability, Development & Education》2005,52(4):345-360
Many researchers have stressed that the acoustic environment is crucial to the speech perception, academic performance, attention, and participation of students in classrooms. Classrooms in highly urbanised locations are especially vulnerable to noise, a major influence on the acoustic environment. The purpose of this investigation was to determine noise levels in one such urban environment, Hong Kong. The ambient noise level, and its relationship to the speech intensity levels of both teachers and students was surveyed in 47 primary school classrooms. Moreover, the presence of acoustical treatments for noise reduction and the use of classroom amplification systems were documented for each classroom. The survey found that the mean occupied noise level was 60.74 dB (A); the mean unamplified and amplified speech‐to‐noise ratios of teachers were 13.53 dB and 18.45 dB, respectively; while the mean unamplified speech‐to‐noise ratio for students was 4.13 dB. Most of the classrooms exhibited insufficient acoustical treatments to provide significant noise reduction. The listening environment in many Hong Kong primary schools was not favourable for optimal classroom learning. Recommendations for improving the acoustical environment in classrooms in highly urbanised locations such as Hong Kong are discussed. 相似文献